This is an open-label, phase I/II trial of recombinant CD4-IgG2 in HIV-infected children. In Part 1 of the study, children will be given single doses of CD4-IgG2 in a dose-escalating fashion. If single doses are tolerated, children will receive CD4-IgG2 once weekly at weeks 0, 1, 2, and 3 at the highest safe dose established in Part 1. Subjects will be monitored for safety, CD4-IgG2 levels, plasma HIV-1 RNA and peripheral blood mononuclear cell quantitative cultures. Part 1 of the study was completed. Six children have completed Part 2. An additional six children will be recruited to receive CD4-IgG2 at a higher dose (20 mg/kg).